Brief Description of the Prior Art
A number of types of quick connecting and disconnecting couplings for joinder of sections of tubular stock have been devised. Such couplings are used for quickly interconnecting ends of a pair of pipeline or conduit or hose sections for the purpose of establishing a fluid-tight coupling through which fluid may flow without leakage. An important desideratum in the design of such couplings is that the coupling be susceptible to manual release, preferably by one hand, and preferably almost instantaneously, so that where it is necessary to immediately interrupt the flow of fluid through the coupling to a remote location, such disconnection can be effected before a disaster or significant economic loss occurs as a result of continued flow of the fluid between the sections and through the coupling.
One type of quick-disconnect coupling which has previously been devised and patented, is that which is described and illustrated in Vargo U.S. Pat. No. 4,647,075, assigned to the assignee of the present application. The Vargo quick-disconnect coupling has a pair of opposed ports provided in the female socket body which has a projecting hose receiving neck. Pairs of spaced lugs are disposed on opposite sides of the two ports, and latching handles are mounted for pivotation in these lug pairs. The latching handles carry cam heads which have camming surfaces located radially inwardly of the female socket body in a position to cooperate with indentations formed in a male coupling element inserted in the female socket body when a pair of hose sections are connected to the coupling elements. A wire safety spring element is mounted adjacent the latching handles, and prevents the handles from prematurely unlatching the male coupling member as a result of vibratory forces.
Krapp U.S. Pat. No. 2,757,944 discloses a coupling which includes a set of cam handles which are cammed into a locked positioned by a pair of cams. When it is desired to bleed off the pressure, one of the handles is positioned as shown in the drawings of this patent so that the cam retains a part of its face in contact with the sealing gasket. The remainder of the face of the cam leaves the sealing gasket when the male member is tilted, thereby providing an opening for pressure to be relieved as shown by arrows in FIG. 3 of the drawings of this patent.
Owens U.S. Pat. No. 3,314,698 discloses a quick-disconnect coupling which includes a female part having a bore receiving a male adapter. The female part carries a cam arm which can be pivoted about a pivot pin so that a cam surface extends through an opening into a recess formed in the male adapter. A spring is provided to hold the cam arm in a locked position. This spring has convolutions wrapped around the hinge pin which passes through and pivotally supports the cam arm.
U.S. Pat. No. 4,519,635 to McMath describes a coupling which includes a set of handles pivotally mounted on the coupling and each including a first cam means and a second cam means. Each handle is provided with a cam surface which is defined by a plurality of cooperating cam surfaces. Such surfaces cooperate to provide a disconnecting movement until a particular position is reached, at which position the disconnection of the parts of the coupling is reversed, and becomes instead an incremental connecting movement occurring over a predetermined increment before allowing the members to be completely disconnected.
Moore U.S. Pat. No. 3,439,942 provides a conventional quick-release coupling made up of male and female coupling elements. It includes a relatively thin, flexible resilient retaining member which includes a planar first portion which is apertured to receive the pin upon which pivotally supports the lever arms used to latch the male and female elements to each other pivots. The retaining member has a second portion which is resilient, and is normally bent at an angle to the plane of the first portion so as to overlie and contact the lever arm and resiliently retain it in position.
Krapp U.S. Pat. No. 2,478,586 discloses a quick-disconnect coupling which includes a tubular insertable member having a seating face on one of its ends, and which insertable member is received within a socket member which includes a tubular portion having an internal shoulder. A gasket on this shoulder is adapted to be engaged by the seating face of the insertable member. A compound arm element having pairs of arms extending at an angle to each other is mounted on the socket member and includes a cam member extending into the socket member and adapted to be engaged and displaced by the end of the insertable member when the latter is inserted. A depression or groove is provided on the insertable member which is adapted to be engaged by the spring loaded pivoted handle on the socket member, and specifically the cam surface thereof, and forced thereby into seating engagement with the gasket.
Krapp U.S. Pat. No. 3,124,374 discloses and describes a self-venting, separable coupling which includes certain safety features which make the coupling particularly useful in connecting sections of a line used to carry a pressurized fluid. As explained in this patent, these types of couplings are in some cases dangerous, because when they are used in conjunction with such high pressure service lines because when they are de-coupled or disconnected through inadvertence at a time when the proper valves are not closed to prevent the continuation of high pressure fluid flow through the coupling. The coupling is then released explosively, and whips and thrashes about, endangering the workmen close by, as well as anyone else in the area.
This patentee recognizes that the prevention of accidents when using this type of coupling depends in large part on giving some type of warning that the coupling is carrying high pressure fluid, and it is equally or even more important that the coupling not be totally released so as to allow loss of fluid and injury to workmen or operators by reason of the thrashing sections of the de-coupled hose, and the high pressure fluid is ejected from the open ends thereof.
The safety lock coupling of Krapp as disclosed in U.S. Pat. No. 3,124,374 comprises male and female members, with the male member having a grooved portion designed to fit into the female member, and to receive in the groove, a locking and clamping means carried on the female member. The clamping means which is provided has a loose position, or release and a clamped position, and is composed of a pair of clamping handles pivoted on the female member, and having cam surfaces adapted to bear against the groove portion of the male member when in the clamped position. The cam surfaces of the clamping handles are so formed as to permit the cam surface to pivot clear of the grooved portion of the male adapter member when the clamping handles are moved to their loose or released positions.
There are further provided, a pair of locking levers which are also pivoted on the female member, and have cam surfaces which project into the groove formed on the male adapter at a time when the locking handles are pivoted to their locking position. The locking handles are designed so that when they are rotated into a release position, the cam surfaces which they carry are substantially withdrawn from the grooved portion of the male member.
In the use of this type of coupling, when the clamping levers are pivoted outwardly, this causes them to pivot on the female member, and to move into their loose or releasing position in which their radially inner cam surfaces are clear of the groove carried on the male member. At this time, however, the locking lever is still in its locking position with its cam surface projecting into the groove portion of the male member and fitting loosely therein. If there is pressure of a high magnitude in the line, it will at this time force the coupling slightly apart, and the loose fit of the locking cam surfaces will permit a slight release of the engagement of the coupling. The pressurized fluid will then leak out of the coupling in small quantities, apprising the operator that there is pressure in the line which needs to be relieved, or else that the high integrity coupling needs to be re-established by reclosing the clamping levers.
If there is no pressure in the line, the operator can fully release or disconnect the coupling by pivoting the locking levers outwardly into the release position so as to totally withdraw the cam surfaces from the groove in the male member. This allows the male member to be moved freely in an axial direction completely out of the female coupling. A detent member is urged by a spring into the path of movement of the locking handle so as to prevent the locking handle from being inadvertently pivoted outwardly to its total release position.
Other U.S. patents disclosing quick-disconnect couplings of the type having a male and female member sealingly interconnected by means of cam arms carried on the female member, with these arms acting through openings therein to engage the groove or recess in the male member are U.S. Pat. Nos. 2,518,026; 2,770,474 and 2,770,256 to Krapp.
Another quick detachable coupling for interconnecting sections of hose or tubing, and which can be quickly disconnected by means of pivoted latching handles carried on the female element is Parrish U.S. Pat. No. 3,195,934.
Another patent which recognizes the problem of adequate safety in a quick-disconnect cam locking coupling of the type involving a male element seated against a seal carried on an internal shoulder of a female coupling element is Goodall U.S. Pat. No. 4,294,670. The Goodall patent provides the usual external peripheral groove around the male element, and enables the male element to be sealingly joined to the female element by providing a pair of camming handles. Each of the camming handles includes a lever arm lying adjacent the female socket, and a cam portion which passes through a lateral or side opening provided in the female socket so as to engage the peripheral groove carried on the male element. Outward movement of the levers of the handles away from the female socket functions to disengage the cam portions from the peripheral groove carried on the male element. Each of the cam members is locked in the groove, however, by a removable wire pin which is engaged by at least one lug on the socket, and is positioned and adapted to limit the outward movement of the cam portion and thereby prevent total mechanical release of the male element from the female socket until the pressure has been bled down to an acceptable level. At this time, the wire pin is removed to allow disengagement of the principle parts of the coupling to then be completed in a safe manner.
Other pipe coupling devices of the general type described are depicted in U.S. Pat. Nos. 3,860,274 to Ledstrom et al, 2,033,142 to Lewis and 3,976,313 to Lauffenburger.
As indicated in some of the foregoing patents in some types of high pressure fluid service, where quick-disconnect couplings are employed, it is desirable to provide a coupling which does not completely mechanically disconnect the tubular sections from each other prior to the time that the pressure of the fluid conveyed through the coupled sections has been bled down or relieved to a sufficiently low level. This avoids the disconnected sections of the coupling and tubing from being forced violently away from each other at the time the coupling is completely disconnected mechanically. Moreover, the sudden escape of high pressure fluid at the instant that the coupling is totally disconnected mechanically can cause dangers of explosion or injury to personnel near the coupling at that time.
At least one type of coupling has been devised which provides for a gradual bleed down or relief of the pressure within the coupling before the coupling is totally mechanically disconnected, and which provides for a controlled release of the pressure at that time.
This coupling is a safety coupling and is referred to in the literature promulgated by the manufacturer, the Ever-Tite Coupling Company, Inc. of New York, New York, as a bleed-off coupler. A male adapter is inserted in a female coupler where the two are connected to the ends of sections of a tubing or conduit intended for high pressure service. The female coupler makes a fluid-tight connection with the male adapter when two pairs of handles which are provided are pivoted to a closing position with a single closing motion. In such instance, two different sets of locking cams are used on the two sets of handles. The function of the two handles is that when the coupling is to be disconnected, only one pair of the handles, called the locking handles, is initially pivoted outwardly, and this has the effect of partially opening the coupling so that it is in a pressure bleed down status. The fact that the fluid carried through the coupling is under high pressure is immediately recognized by the operator, and the coupling can then either be quickly re-closed by pivoting the locking handles to the locking position, or the coupling can be left in the bleed-off position until the high pressure of the fluid that is carried in the conduits is relieved. After this occurs, the coupling can then be safely and completely disconnected mechanically by pivoting the safety handles included in the second set of handles downwardly to a total release position.